1) Field of the invention
The packing and transportation of products which can flow (particularly liquid products) have long posed an awkward problem.
Although pulverulent products can be transported in other ways, the invention provides an advantageous alternative.
Metal containers and glass containers are markedly less commonly used than in the past : they are generally heavy, permitting little variation in form, and are relatively expensive. Glass containers are, moreover, breakable, which is a major disadvantage. As for metal containers, these are easily deformed irreversibly if they are dropped.
Consequently, for a few decades now, the use of various containers made from plastic material has become commonplace for packing, inter alia, liquid food products, or for use in industry or in every day life.
All kinds of containers which were formerly made from glass or metal have therefore gradually been replaced by containers made from plastic material which are intended for the same types of use. These new containers permit easier handling and treatment, particularly by virtue of the reduction in risks of breakage or harmful deformations.
A number of problems specific to the use of plastic materials for packaging liquid products have appeared over time, some of which still exist today, which the present invention attempts to remedy.
For reasons of economy, it is desirable for containers made from plastic material to be as light as possible.
With this in mind, and on the basis of forms copied from glass or metal packaging, packaging in plastic material has gradually evolved towards forms which are better adapted to the characteristics of the material, these forms making it possible to optimize resistance to vertical compression, the limit being given by a non-visible and non-permanent deformation of the packaging.
Most of the forms developed which have both good resistance to vertical compression and a light weight nevertheless have a major drawback : the ratio between the volume occupied by the spatial requirement of the packaging and the volume of the liquid product packed is high and in all cases never reaches the optimum value of 1:1. In tear drop-shaped bottles, for example, this ratio is generally greater than 2:1. The loss of volume is thus huge and considerably increases packaging, handling, storage and distribution costs.
Due to their rigidity, most containers made from plastic material also take up considerable space in the volume of domestic or industrial waste. It can easily be understood that it is desirable for this volume to be minimized.
2) Description of the prior art
Extremely light packaging made from plastic material which, after use, occupies a particularly small volume has been on the market for a long time. This packaging is, namely, envelopes or the like made from flexible plastic material, also referred to as sachets, which are provided for packing shampoos, conditioners or food products such as milk. This type of packaging is, however, rarely used, since it is extremely impracticable. Once opened, the envelopes cannot in fact be closed again or kept upright. It is thus necessary to use their contents in one go. Moreover, as there is a thin film without external protection, the risks of leakage are considerable.
Plasticized cardboard boxes of the brick type for milk make it possible to save space during transportation and storage. They comprise a small quantity of plastic material and, after use, occupy a small volume in refuse provided that care is taken to flatten them.
These boxes are manufactured from a cardboard sheet. At least one layer of polyethylene and, optionally, a layer of another material such as aluminium are made integral with the cardboard sheet by being stuck together or by other means. This results in a particularly troublesome drawback from the ecological stand-point : the materials which form the single composite layer of the packaging cannot be dissociated from one another and thus cannot be separated by simple means. Thus, they can neither be destroyed selectively by incineration nor be recovered for the purposes of recycling. Also, since the actual cardboard has been plasticized, it is rendered rot proof.
The method of opening boxes of the brick type for milk is as follows : the user must lift a part, which is folded on the top of the box and folded over the sides, and cut off its corner. If the cutting operation is not performed correctly, which often occurs, milk is spilt when the user picks up the brick in order to pour out its contents. No provision is made, after opening, for the possibility of reclosing this type of packaging.
For packing liquid washing agents, packaging formed from a combination of cardboard and sheets of plastic materials which can, in certain cases, be reclosed each time the product is used, has recently been developed.
Particularly, packaging of the brick type for milk described above, whose method of opening is different, has been marketed : a pouring spout, consisting of an injection-moulded component made from polyethylene, is glued to the center of the upper wall of the box. When using the container for the first time, the consumer must himself pierce a hole in the wall of the packaging, through the spout, thus creating lips which face the inside of the box and which prevent total emptying of the box. As the spout is applied to the outer part of the composite film forming the wall of the packaging, it can become detached in the event of impact or rough treatment. As with bricks for milk, any recycling of plastic material or of cardboard is impossible.
Moreover, stacking and palletization are difficult due to the projecting pouring spout.
Another type of packaging known on the market and provided for liquid washing agents permits easier pouring of the product. This is packaging which consists of a cardboard sheet which has been given the form of a box, in which a sheet of plastic material welded into the form of a bag is glued at several points. The upper wall of this packaging is manufactured with an off-center hole. A spout which is integral with the cardboard and with the sheet of plastic material is positioned at the location of the hole provided on the top of the box. Opening, closing and pouring of the product are relatively easy. Nevertheless, it is observed that, in practice, due in particular to the parallelepipedal form of the box, it is also virtually impossible to empty.
Once again, the components (cardboard and plastic material) are very difficult to dissociate from one another, which is undesirable from an ecological stand-point. Moreover, this type of packaging requires the use of a considerable amount of adhesive. Finally, the problems of stacking and palletization are still not solved.
There is a particular model of this type of packaging which has a large opening provided in the cover. The spout, which is then integral only with the sheet of plastic material, is able to retract into the box via this opening. What frequently happens now is that it moves obliquely and disappears inside the box, from where it is then awkward to recover. The direction of the flow of product is not guaranteed either, on pouring.
There is also another particular model of this type of packaging, in which the spout is located in a "cut corner" of the cardboard box. In this case, the resistance of the packaging to vertical compression is diminished.
The packaging mentioned above is not designed in order to be filled via the spout. It must be manufactured and filled by complicated and expensive machines which make the cardboard, apply the plastic material thereto and proceed immediately to filling. In each case, this means that the manufacturer of the packaged product must transport his merchandise in bulk to the premises where the packaging is manufactured or invest in machines for manufacturing and filling the packaging, which involves additional cost.
U.S. Pat. No. 4,143,718 describes a packaging comprising a container surrounded by a cardboard box. The design of the carton is such that it is impossible to carry out filling of the completely assembled container on a conventional filling line. It is necessary either to previously fill the inner container (which, in this case, has itself to be relatively rigid, such as a glass bottle), or to break down the folding of the carton into two partial folding operations, which complicates the apparatus of the chain. Once packing is finished, the spout is in fact accessible only by tearing part of the carton.
Application GB 2,228,725 describes a packaging composed of a container in plastic material surrounded by a carton. The orifice of the container is arranged set back relative to the upper face of the carton so as not to extend beyond the latter. The orifice of such a container, clearly intended to contain corrosive liquids, is connected, for draining, to a pumping device. In this case, there is no pouring problem.